There are a number of situations in which antennas are used in field environments. For example, animals are often tagged with radio transmitters which enable the monitoring of migratory and/or territorial habits. The location of such tagged animals is often monitored by a radio receiver attached to a hand-held antenna. Other examples of situations in which antennas are used in field environments include the tracking of hunting dogs that are equipped with radio transmitters, military field tracking operations, weather balloon tracking, etc.
In field environments associated with such procedures, the use of an antenna having fixed or rigid elements can be bothersome, particularly when it is necessary to move through forests, woods, and other areas of brush or vegetation.
Antennas typically used for tracking or locating radio transmitter-tagged objects comprise planar structures which include a plurality of rigid dipole elements that extend from a central boom. As is known, the length of the dipole elements can vary, depending on the frequency of the signal which is to be received.
The use of flexible antenna elements has been suggested in remotely deployable antennas. U.S. Pat. Nos. 5,214,439 and 5,196,858 to Reed disclose deployable antennas which include S-shaped antenna elements that are wound around spools located in an elongated housing or drum. The antenna elements are deployed or extended from the drum by rotating the spools relative to the drum. U.S. Pat. No. 4,977,408 to Harper et al. discloses a deployable antenna which is similar to the deployable antennas of Reed. The deployable antenna of Harper et al. utilizes C-shaped antenna elements which are wound around spools.
U.S. Pat. No. 4,355,315 to Zoulek discloses a log periodic directional antenna which includes a plurality of stainless steel spring-type antenna elements that are provided as half elements which are mounted to opposite sides of the boom. Zoulek's antenna is designed to provide either horizontal or vertical polarization when mounted to a mast.
The present invention provides an antenna having flexible elements which allows the antenna to be used in rough field environments where the antenna is likely to encounter various obstacles during use.